A Study on the Pressure Distribution along the Powder-Die Interfaces in Powdered Metal Compaction Process
This paper is concerned with the pressure distribution along the die-powder interface in long parts. The pressure exerted on the interface at various points on the moving and stationary punch, and also on the sidewall of container was investigated by the finite element method. A plasticity theory describing asymmetric behavior of powdered metals in tension and compression was briefly summarized. The yield criterion applied to the sintered powdered metals had been modified for describing this asymmetric behavior. The material properties of copper powders under compaction were also briefly described for the completeness of the paper. The copper powders were selected as a model material in the present study. The main purpose of this study is to investigate the pressure distribution along the interface of tooling quantitatively by the finite element method so that the results could be applied usefully to the design of tooling, especially container design for powdered metal compaction. Geometrical condition for analysis was confined to the Class II components which is very long parts without steps. It was concluded from the simulation results that the pressure exerted on the moving punch increases sharply near the outer circumference of punch and the pressure on the sidewall decreases at a distance from moving punch to fixed punch. It was also seen from the simulation that the pressure on the stationary punch is not significantly built up and decreases toward outer periphery. These trends were seen amplified with severe frictional conditions imposed on the tooling and powder interface.
N. Ohno and T. Uehara
H.S. Koo et al., "A Study on the Pressure Distribution along the Powder-Die Interfaces in Powdered Metal Compaction Process", Key Engineering Materials, Vols. 340-341, pp. 655-658, 2007